[lipi] Add utils for working with ISO and ICU

Features:
- Add `to_iso_15924_code`, `to_iso_15924_numeric_code`, and
  `to_icu_numeric_code`.
- Update `detect` to support `Cham`, `Kharoshthi`, `MeeteiMayek`,
  `Iso15919`, `Wx`, and `BarahaSouth`.
- Add better support for nuktas, Om, and various punctuation.
- Add better support for svaras, ayogavahas, and the combination of
  svaras and ayogavahas.

Code:
- Simplify and clean up `create_schemes.py`.

vidyut-lipi/Cargo.toml

@@ -23,4 +23,5 @@ console_error_panic_hook = "0.1.7"
 crate-type = ["cdylib", "rlib"]
 
 [dev-dependencies]
+codes-iso-15924 = { version = "0.1.3", default-features = false }
 unicode-normalization = "0.1.22"